title: Purine biosynthesis-deficient Burkholderia mutants are incapable of symbiotic accommodation in the stinkbug.
abstract: The Riptortus-Burkholderia symbiotic system represents a promising experimental model to study the molecular mechanisms involved in insect-bacterium symbiosis due to the availability of genetically manipulated Burkholderia symbiont. Using transposon mutagenesis screening, we found a symbiosis-deficient mutant that was able to colonize the host insect but failed to induce normal development of host's symbiotic organ. The disrupted gene was identified as purL involved in purine biosynthesis. In vitro growth impairment of the purL mutant and its growth dependency on adenine and adenosine confirmed the functional disruption of the purine synthesis gene. The purL mutant also showed defects in biofilm formation, and this defect was not rescued by supplementation of purine derivatives. When inoculated to host insects, the purL mutant was initially able to colonize the symbiotic organ but failed to attain a normal infection density. The low level of infection density of the purL mutant attenuated the development of the host's symbiotic organ at early instar stages and reduced the host's fitness throughout the nymphal stages. Another symbiont mutant-deficient in a purine biosynthesis gene, purM, showed phenotypes similar to those of the purL mutant both in vitro and in vivo, confirming that the purL phenotypes are due to disrupted purine biosynthesis. These results demonstrate that the purine biosynthesis genes of the Burkholderia symbiont are critical for the successful accommodation of symbiont within the host, thereby facilitating the development of the host's symbiotic organ and enhancing the host's fitness values.
authors.affiliation: Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan, South Korea.
authors.forename: Jiyeun Kate
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan, South Korea.
authors.forename: Ho Am
authors.initials: HA
authors.lastname: Jang
authors.affiliation: Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan, South Korea.
authors.forename: Yeo Jin
authors.initials: YJ
authors.lastname: Won
authors.affiliation: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, Sapporo, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Kikuchi
authors.affiliation: Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan, South Korea.
authors.forename: Sang
authors.initials: S
authors.lastname: Heum Han
authors.affiliation: Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan, South Korea.
authors.forename: Chan-Hee
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Liberal arts, The Open University of Japan, Chiba, Japan.
authors.forename: Naruo
authors.initials: N
authors.lastname: Nikoh
authors.affiliation: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan. t-fukatsu@aist.go.jp.
authors.forename: Takema
authors.initials: T
authors.lastname: Fukatsu
authors.affiliation: Global Research Laboratory, College of Pharmacy, Pusan National University, Pusan, South Korea. brlee@pusan.ac.kr.
authors.forename: Bok Luel
authors.initials: BL
authors.lastname: Lee
mesh_terms: D000818:Animals; D018441:Biofilms; D019117:Burkholderia / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D017344:Genes, Insect; D020062:Heteroptera / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D011687:Purines / Q000096:biosynthesis*; D013559:Symbiosis
chemical_list: D011687:Purines; C030985:purine